This invention relates to the manner in which splices in polymer coated metal tapes are recoated. More particularly, it relates to an adhesive tape for overcoating the splices in polymer coated metal tapes and thereby recoating the same in the area where the polymer coating is lost when weld splices are made.
The use of polymer coated metal tapes in electrical cable constructions is well known. For example such metal tapes are commonly used as shields in communication cables and, as such, they are generally known as shielding tapes. Plastic coated aluminum tape is preferably used for this purpose, however plastic coated steel tapes or plastic coated copper tapes or combinations of various plastic coated metal tapes are also well known.
A typical manufacturing line for the manufacture of tape shielded cable requires a payoff for the tape; a tape splicing station when the ends of the individual tapes are spliced or joined together, usually by spot welding or other butt-jointing techniques; a device to accumulate tape, while splicing on a new length of tape is performed; if necessary, a device for corrugating the tape which is then passed through a conventional device that guides the cable core while having the corrugated tape surround the core; and finally the combination is fed to an extruder for applying an outer jacket of thermoplastic material, such as polyethylene. Since waterproofing is usually required, the core is normally filled with a filling compound such as INSOJELL C-3589, which is a trade name of a filling compound produced and supplied by Dussek Campbell Limited.
When plastic coated metal tapes, such as Zetabon (trade name of Dow Chemical), are spliced, the original plastic coating is removed from the ends to be spliced, which ends are then spot welded to one another. Customer and industry specifications require that the coating be restored in the spliced area. The current method of restoring the coating is to use an iron-like device to melt the recoating tape onto the metal, thereby providing a heat sealing of the polymer coating to the splice by application of heat and pressure. An example of such method is disclosed, for example, in U.S. Pat. No. 4,319,938. Such heat sealing is time consuming and requires special heat sealing equipment, resulting in additional capital expenditure. It is also greatly dependent on operator's expertise since the amount of heat, pressure and time of application are very much a factor in the satisfactory recoating and are directly controlled by the operator.